In the prior art, it is known to make a jig for securing a specific casting to permit the castings to be cleaned, cut and otherwise worked upon manually or by manually operated tools. Such fixtures must be specifically designed to hold a specific form of casting and usually constitute simple clamp arrangements arranged to interfere as little as possible with the various cleaning and machining operations to be performed on the castings. Such fixture cannot be used with other castings because of their custom nature.
A problem, therefore, to be overcome is to provide a universal type of fixture that can interface with some portion of the casting that is generally similar on all types of castings, particularly tree or "gate" types of castings. In such castings, a central runner usually connects the castings with the sprue. The runner extends longitudinally of the casting and the elements to be molded are usually symmetrically located with respect to such runner. In the prior art, applicant is not aware that it has previously been contemplated to provide specially shaped surfaces on the runners of various casting configurations, which runner surfaces can interface with a supporting jig for accurately locating and fixing a casting for subsequent mechanical operations to be performed on the castings.